JP6807384B2 - Film, molded product and film manufacturing method - Google Patents

Description

The present invention relates to films, molded articles and methods for producing films.

In recent years, stretchable polyolefin films and the like have been used as stretch films for the purpose of preventing cargo from collapsing, preventing stains, protecting the luggage to be transported, and packaging meat, fresh fish, fruits and vegetables, etc. It is also being converted.

As described above, stretch films have been widely used in recent years, but since it is difficult to achieve both stretchability and gas barrier properties that effectively block water vapor and oxygen, they are used in applications that require gas barrier properties. At present, the film thickness is increased at the expense of stretchability, or the number of windings is increased.

As a measure for overcoming the above situation, Japanese Patent Application Laid-Open No. 2014-51037 proposes a stretch film having a gas barrier layer containing a specific allyl alcohol-based polymer.

However, in the stretch film described in JP-A-2014-51037, there is a possibility that the gas barrier property in the state where the tension is released after stretching by applying tension during use may be lower than that before stretching. If the gas barrier property is lowered after the tension is released, there is a disadvantage that it becomes difficult to maintain the gas barrier property when the stretch film is used repeatedly.

On the other hand, the film having gas barrier property is bonded to the film-like rubber material, and has gas barrier property such as inner liner of pneumatic tire, silage film, gasket, inner bag of accumulator, pneumatic ball, air spring and the like. It may be applied to the required product. Even in such a product, there is a disadvantage that the gas barrier property is lowered due to tension applied during use.

Japanese Unexamined Patent Publication No. 2014-51037

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a film capable of suppressing a decrease in gas barrier property due to use, a molded product using the same, and a method for producing the film. is there.

The invention made to solve the above problems includes a gas barrier resin having a glass transition temperature of 70 ° C. or lower and an elastomer, and has an oxygen permeability coefficient of 200 mL / (m ² · day · atm) or less at 20 ° C. By applying tension in the MD direction, the stretched state at a double stretching ratio is maintained for 30 seconds, the length in the MD direction after the tension is released is L ₂ , and the length in the MD direction before the tension is applied. the ratio _L 2 / _{L 1} is a film is 1.5 or less when the _{L 1} to is.

The above-mentioned "glass transition temperature" refers to a value obtained by a differential scanning calorimetry method (DSC method) according to JIS K 7121 (2012). The above-mentioned "oxygen permeability coefficient" refers to an oxygen permeability coefficient measured according to JIS K 7126-2 (2006) under the conditions of a temperature of 20 ° C. and a relative humidity of 65%. The "MD direction" is the transport direction of the film at the time of molding, and is the orientation direction of the polymer crystals of the gas barrier resin. The orientation direction of the polymer crystals of the gas barrier resin can be confirmed by, for example, wide-angle X-ray diffraction measurement, birefringence measurement, or the like.

By having the above structure, the film can suppress a decrease in gas barrier property due to use. The reason why the film has the above-mentioned structure and exerts the above-mentioned effect is not clear, but it is presumed as follows. That is, by using a gas barrier resin having a glass transition temperature of 70 ° C. or less, the length ratio L ₂ / L ₁ in the MD direction before and after tension application is set to 1.5 or less while suppressing the occurrence of cracks in the gas barrier resin during stretching. By doing so, it is possible to suppress the decrease in the thickness of the film when the tension is released after stretching, and it is considered that the decrease in the gas barrier property due to use can be suppressed.

When the respective _{E MD} and _{E TD} elongation at break in the MD direction and the TD direction of the film, preferably 0.9 to 1.7 as the ratio _E TD _{/ E MD} elongation at break. By setting the ratio _ETD / _EMD within the above range, the impact resistance can be improved and the decrease in gas barrier property due to use can be further suppressed. The "TD direction" is the width direction of the film at the time of molding, and is a direction orthogonal to the orientation direction of the polymer crystals of the gas barrier resin. The "breaking elongation" means the breaking elongation measured according to ISO527-2 under the conditions of a temperature of 23 ° C. and a relative humidity of 50%.

As the gas barrier resin, an ethylene-vinyl alcohol copolymer is preferable. By using an ethylene-vinyl alcohol copolymer as the gas barrier resin, the gas barrier property and the melt moldability can be improved.

It is preferable to have at least one gas barrier layer (A) formed from the polymer containing the gas barrier resin and at least one elastomer layer (B) formed from the polymer containing the elastomer. With this configuration, stretchability can be improved while maintaining gas barrier properties.

The total number of layers of the gas barrier layer (A) and the elastomer layer (B) is preferably 7 or more, more preferably 9 or more, and particularly preferably 15 or more. With this configuration, it is possible to suppress the continuous occurrence of defects such as pinholes and cracks when bent, and thus the durability can be improved. Further, it is preferable to have a laminated structure in which the gas barrier layer (A) and the elastomer layer (B) are alternately laminated. With this configuration, it is possible to further suppress the continuous occurrence of defects such as pinholes and cracks, so that the durability can be further improved.

The elastomer layer (B) has at least one elastomer layer (B1) formed of a polymer containing a hydrocarbon-based elastomer, and at least one layer of the elastomer layer (B1) is laminated as the outermost layer. Is preferable. With this configuration, the adhesion between the elastomer layer (B1), which is the outermost layer, and the transport roll can be suppressed during molding of the film, so that excessive stretching during molding of the film can be suppressed. As a result, the length ratio L ₂ / L ₁ in the MD direction before and after the tension is applied can be controlled within a more appropriate range.

It is preferable that the polymer forming the elastomer layer (B1) contains a styrene-based elastomer having a double bond. For example, when the film and the film-like rubber material are bonded together and applied to an inner liner of a pneumatic tire, an inner bag of an accumulator, etc., the outermost elastomer layer (B1) and the rubber material are vulcanized or the like. Since the cross-linking reaction can be carried out, the adhesiveness between the elastomer layer (B1) and the rubber material can be improved.

As the elastomer layer (B), it is preferable to further have an elastomer layer (B2) formed of a polymer other than the polymer containing the hydrocarbon-based elastomer. With this configuration, stretchability can be further enhanced. In this case, it is preferable that the polymer of the elastomer layer (B2) contains a polyurethane-based elastomer. With this configuration, stretchability can be further enhanced.

Another invention made to solve the above problems is a molded product provided with the film of the present invention. According to the molded product, since the film of the present invention is provided, the gas barrier property of the film can be maintained even if the film is stretched when the molded product is molded or used, for example.

It is preferable to further include a diene rubber layer (C) laminated on the outer surface of the film. With this configuration, for example, the molded product can be applied to an inner liner of a pneumatic tire, a silage film, a gasket, an inner bag of an accumulator, a pneumatic ball, an air spring, and the like.

Yet another invention made to solve the above problems is a method for producing the film, which comprises a step of coextruding a polymer containing a gas barrier resin and a polymer containing an elastomer. According to the production method, the film having the gas barrier layer (A) and the elastomer layer (B) can be easily and surely produced.

According to the present invention, it is possible to provide a film capable of suppressing a decrease in gas barrier property due to use, a molded product using the same, and a method for producing the film.

FIG. 1A is a schematic cross-sectional view showing a film according to an embodiment of the present invention. FIG. 1B is a schematic cross-sectional view showing a film of an embodiment different from that of FIG. 1A. FIG. 2 is a schematic cross-sectional view for explaining a method for producing a film according to an embodiment of the present invention. FIG. 3A is a schematic cross-sectional view showing a molded product including the film of FIG. 1A. FIG. 3 (b) is a schematic cross-sectional view showing a molded product including the film of FIG. 1 (b).

Hereinafter, a film according to an embodiment of the present invention, a method for producing the same, and a molded product will be described in detail.

<Film>
The film according to one embodiment of the present invention contains a gas barrier resin having a glass transition temperature (hereinafter, also referred to as “Tg”) of 70 ° C. or lower, and an elastomer. The film according to the present embodiment, the oxygen permeability coefficient is at ^{200mL / (m 2 · day ·} atm) or less, a state stretched at twice the draw ratio by applying tension in the MD direction at 20 ° C. maintained for 30 seconds, when the length L ₂ of the MD direction after releasing the _tension in the MD direction before application of the tension length was L _1, ratio of the length of the MD direction L _{2 /} L ₁ is 1.5 or less. By having the above-mentioned structure, the film according to the present embodiment can suppress a decrease in gas barrier property due to use.

The film according to this embodiment is not limited in its structure as long as it has the above structure, and may be, for example, a single-layer film formed of a resin composition in which elastomer particles are dispersed in a gas barrier resin. At least one gas barrier layer (A) formed from a polymer containing a gas barrier resin (hereinafter, also referred to as “A layer”) and at least one elastomer layer (B) (hereinafter, also referred to as “A layer”) formed from a polymer containing an elastomer. , Also referred to as “B layer”), preferably a laminated film. By using the laminated film, the stretchability can be improved while maintaining the gas barrier property.

[Gas barrier resin]
The gas barrier resin is a polymer that is the main component of the A layer. The lower limit of the content of the gas barrier resin in the A layer (material for forming the A layer) is, for example, 60% by mass, preferably 90% by mass, more preferably 95% by mass, still more preferably 99% by mass, and 99. 9.9% by weight may be even more preferred. The gas barrier resin is a resin having a function of preventing gas permeation and having a Tg of 70 ° C. or lower. The "resin having a function of preventing the permeation of gas" is a resin such as oxygen permeability coefficient of the film having an average thickness of 20μm formed by the resin becomes 200mL / (m 2 · day · atm) or less, A resin having a value of 150 mL / (m ² · day · atm) or less is preferable, a resin having a value of 100 mL / (m ² · day · atm) or less is more preferable, and a resin having a value of 50 mL / (m ² · day · atm) or less is preferable. more ^{preferably, 10mL / (m 2 · day} · atm) or less and consisting resins are particularly preferred.

Examples of such a gas barrier resin include ethylene-vinyl alcohol copolymer (hereinafter, also referred to as “EVOH”), polyamide, polyester, polyvinylidene chloride, acrylonitrile copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, and polyvinylidene. From resins such as alcohol, those having a Tg of 70 ° C. or lower can be selected. The Tg can be controlled by adjusting the composition of the monomer forming the resin, the tacticity, the chain structure, the molecular weight of the resin, and the like.

The upper limit of Tg of the gas barrier resin is 70 ° C., preferably 65 ° C., and more preferably 60 ° C. By setting the Tg to the above preferable upper limit or less, the generation of cracks in the gas barrier resin during stretching can be further suppressed, so that the deterioration of the gas barrier property due to use can be further suppressed. On the other hand, the lower limit of Tg of the gas barrier resin is not particularly limited, but is preferably 30 ° C., more preferably 40 ° C. from the viewpoint of moldability.

Among these gas barrier resins, polyamide, polyester and EVOH are preferable from the viewpoint of gas barrier properties, and in addition to gas barrier properties, melt moldability and adhesiveness between the A layer and the B layer in the case of the above laminated film are improved. From the viewpoint, EVOH is more preferable.

(polyamide)
The polyamide is a polymer having an amide bond, and can be obtained by ring-opening polymerization of lactam, polycondensation of aminocarboxylic acid, polycondensation of diamine and dicarboxylic acid, and the like.

Specific polyamides include, for example, polycaprolactam (nylon 6), polylaurolactum (nylon 12), polyhexamethylene diazipamide (nylon 66), polyhexamethylene azelamide (nylon 69), polyhexamethylene sebacamide. (Nylon 610), nylon 46, nylon 6/66, nylon 6/12, condensate product of 11-aminoundecanoic acid (nylon 11) and other aliphatic polyamides, polyhexamethylene isophthalamide (nylon 6I), Examples thereof include aromatic polyamides such as metaxylylene diamine / adipic acid copolymer (nylon MXD6) and metaxylylene diamine / adipic acid / isophthalic acid copolymer. These can be used alone or in admixture of two or more. Among these polyamides, nylon 6 and aromatic polyamides are preferable, and nylon MXD6 is more preferable because they have excellent gas barrier properties.

(polyester)
Polyester is a polymer having an ester bond, and can be obtained by polycondensation of a polyvalent carboxylic acid and a polyol. Specific examples of the polyester include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyglycolic acid (PGA), polylactic acid (PLA), and all-aromatic liquid crystal polyester. These can be used alone or in admixture of two or more. Among these polyesters, PGA, PLA and all-aromatic liquid crystal polyesters are preferable, and PGA is more preferable, from the viewpoint of high gas barrier property.

(EVOH)
EVOH is a polymer having an ethylene unit and a vinyl alcohol unit as a main structural unit. In addition to the ethylene unit and the vinyl alcohol unit, the EVOH may contain one or a plurality of other structural units.

This EVOH is usually obtained by polymerizing ethylene and vinyl ester and saponifying the obtained ethylene-vinyl ester copolymer.

The lower limit of the ethylene unit content of EVOH (that is, the ratio of the number of ethylene units to the total number of monomer units in EVOH) is preferably 3 mol%, more preferably 10 mol%, still more preferably 20 mol%. , 25 mol% is particularly preferred. On the other hand, as the upper limit of the ethylene unit content of EVOH, 70 mol% is preferable, 60 mol% is more preferable, 55 mol% is further preferable, and 50 mol% is particularly preferable. If the ethylene unit content of EVOH is smaller than the above lower limit, the gas barrier property of the film under high humidity may be lowered, or the melt moldability may be deteriorated. On the contrary, if the ethylene unit content of EVOH exceeds the above upper limit, the gas barrier property of the film may be lowered.

The lower limit of the degree of saponification of EVOH (that is, the ratio of the number of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in EVOH) is preferably 80 mol%, more preferably 95 mol%, and 99 mol%. Is particularly preferable. On the other hand, the upper limit of the degree of saponification of EVOH is preferably 99.99 mol%. If the degree of saponification of EVOH is less than the above lower limit, the melt moldability may be lowered, the gas barrier property of the film may be lowered, and the color resistance and moisture resistance may be unsatisfactory. .. On the contrary, when the degree of saponification of EVOH exceeds the above upper limit, it cannot be expected that the gas barrier property or the like will increase with respect to the increase in the production cost of EVOH. Such EVOH can be used alone, but an embodiment in which it is blended with EVOH having a saponification degree of more than 99 mol% is also suitable.

EVOH is at least a structural unit (I) represented by the following formula (I), a structural unit (II) represented by the following formula (II), and a structural unit (III) represented by the following formula (III). It is preferable to have any one of them. When EVOH has such a structural unit, the bending resistance and the like of the obtained laminate can be further improved.

In the above formula (I), R ¹ , R ² and R ³ are independently hydrogen atoms, aliphatic hydrocarbon groups having 1 to 10 carbon atoms, and alicyclic hydrocarbon groups having 3 to 10 carbon atoms. It represents an aromatic hydrocarbon group or hydroxyl group having 6 to 10 carbon atoms. Further, the pair of R ¹ , R ² and R ³ may be connected. In addition, some or all of the hydrogen atoms of the above-mentioned aliphatic hydrocarbon group having 1 to 10 carbon atoms, alicyclic hydrocarbon group having 3 to 10 carbon atoms, and aromatic hydrocarbon group having 6 to 10 carbon atoms It may be substituted with a hydroxyl group, a carboxyl group or a halogen atom.

In the above formula (II), R ⁴ , R ⁵ , R ⁶ and R ⁷ are independently hydrogen atoms, aliphatic hydrocarbon groups having 1 to 10 carbon atoms, and alicyclic hydrocarbons having 3 to 10 carbon atoms. It represents a hydrogen group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group. Further, R ⁴ and R ⁵ or R ⁶ and R ⁷ may be combined. In addition, some or all of the hydrogen atoms of the above-mentioned aliphatic hydrocarbon group having 1 to 10 carbon atoms, alicyclic hydrocarbon group having 3 to 10 carbon atoms, and aromatic hydrocarbon group having 6 to 10 carbon atoms are included. It may be substituted with a hydroxyl group, an alkoxy group, a carboxyl group or a halogen atom.

In the above formula (III), R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently hydrogen atoms, aliphatic hydrocarbon groups having 1 to 10 carbon atoms, and alicyclic hydrocarbons having 3 to 10 carbon atoms. It represents a hydrogen group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group. In addition, some or all of the hydrogen atoms of the above-mentioned aliphatic hydrocarbon group having 1 to 10 carbon atoms, alicyclic hydrocarbon group having 3 to 10 carbon atoms, and aromatic hydrocarbon group having 6 to 10 carbon atoms are included. It may be substituted with a hydroxyl group, an alkoxy group, a carboxyl group or a halogen atom. R ¹² and R ¹³ independently represent a hydrogen atom, a formyl group, or an alkanoyl group having 2 to 10 carbon atoms.

The lower limit of the content of the structural units (I), (II) or (III) with respect to all the structural units is preferably 0.5 mol%, more preferably 1 mol%, still more preferably 1.5 mol%. On the other hand, the upper limit of the content of the structural unit (I), (II) or (III) is preferably 30 mol%, more preferably 15 mol%, still more preferably 10 mol%. When EVOH has the structural units shown in (I), (II) or (III) in the above range, the flexibility and processing properties of the polymer forming the A layer are improved, and as a result, the stretchability of the film is improved. And thermoformability can be improved.

In the structural unit (I), (II) or (III), examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms include an alkyl group and an alkenyl group, and an alicyclic hydrocarbon having 3 to 10 carbon atoms. Examples of the hydrogen group include a cycloalkyl group and a cycloalkenyl group, and examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms include a phenyl group and the like.

In the structural unit (I), R ¹ , R ² and R ³ are preferably hydrogen atoms, methyl groups, ethyl groups, hydroxyl groups, hydroxymethyl groups and hydroxyethyl groups, respectively, among these. It is more preferable that they are independently hydrogen atoms, methyl groups, hydroxyl groups and hydroxymethyl groups, respectively. By having such R ¹ , R ² and R ³ , the stretchability and thermoforming property of the film can be further improved.

The method of containing the structural unit (I) in EVOH is not particularly limited, but for example, in the polymerization of ethylene and vinyl ester, a method of copolymerizing a monomer induced by the structural unit (I) may be used. Can be mentioned. Examples of the monomer derived from this structural unit (I) include alkenes such as propylene, butylene, pentene, and hexene; 3-hydroxy-1-propene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, and 4 -Asiloxy-1-butene, 3,4-diasiloxy-1-butene, 3-acyloxy-4-hydroxy-1-butene, 4-acyloxy-3-hydroxy-1-butene, 3-acyloxy-4-methyl-1 -Buten, 4-Asiloxy-2-methyl-1-butene, 4-Asiloxy-3-methyl-1-butene, 3,4-diasiloxy-2-methyl-1-butene, 4-hydroxy-1-pentene, 5 -Hydroxy-1-pentene, 4,5-dihydroxy-1-pentene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diasiloxy-1-pentene, 4-hydroxy-3-methyl -1-Pentene, 5-Hydroxy-3-methyl-1-pentene, 4,5-dihydroxy-3-methyl-1-pentene, 5,6-dihydroxy-1-hexene, 4-hydroxy-1-hexene, 5 -Hydroxy-1-hexene, 6-hydroxy-1-hexene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-hexene, 5,6-diasiloxy-1-hexene, etc. Examples thereof include alkene having a hydroxyl group or an ester group. Among them, from the viewpoint of copolymerization reactivity and gas barrier property of the obtained laminate, propylene, 3-acetoxy-1-propene, 3-acetoxy-1-butene, 4-acetoxy-1-butene and 3, 4-Diacetoxy-1-butene is preferred. In the case of an alkene having an ester, it is induced to the structural unit (I) during the saponification reaction.

In the structural unit (II), it is preferable that both R ⁴ and R ⁵ are hydrogen atoms. In particular, it is more preferable that both R ⁴ and R ⁵ are hydrogen atoms, one of R ⁶ and R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and the other is a hydrogen atom. The aliphatic hydrocarbon group is preferably an alkyl group or an alkenyl group. From the viewpoint of particularly placing importance on the gas barrier property of the film, it is particularly preferable that one of R ⁶ and R ⁷ is a methyl group or an ethyl group and the other is a hydrogen atom. It is also particularly preferable that one of R ⁶ and R ⁷ is a substituent represented by (CH ₂ ) _h OH (where h is an integer of 1 to 8) and the other is a hydrogen atom. In the substituent represented by (CH ₂ ) _h OH, h is preferably an integer of 1 to 4, more preferably 1 or 2, and particularly preferably 1.

The method for containing the structural unit (II) in EVOH is not particularly limited, but a method for containing EVOH obtained by a saponification reaction by reacting it with a monovalent epoxy compound is used. As the monovalent epoxy compound, compounds represented by the following formulas (IV) to (X) are preferably used.

In the above formulas (IV) to (X), R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ are independently hydrogen atoms and aliphatic hydrocarbon groups having 1 to 10 carbon atoms (alkyl groups, respectively. It represents an alicyclic hydrocarbon group having 3 to 10 carbon atoms (cycloalkyl group, cycloalkenyl group, etc.) or an aliphatic hydrocarbon group having 6 to 10 carbon atoms (phenyl group, etc.). Further, i, j, k, p and q each independently represent an integer of 1 to 8.

Examples of the monovalent epoxy compound represented by the above formula (IV) include epoxy ethane (ethylene oxide), epoxy propane, 1,2-epoxybutane, 2,3-epoxybutane, and 3-methyl-1,2-epoxy. Butane, 1,2-epoxypentane, 3-methyl-1,2-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 3-methyl-1,2-epoxy Hexane, 3-methyl-1,2-epoxy heptane, 4-methyl-1,2-epoxy heptane, 1,2-epoxy octane, 2,3-epoxy octane, 1,2-epoxy nonane, 2,3-epoxy Nonan, 1,2-epoxydecane, 1,2-epoxydodecan, epoxyethylbenzene, 1-phenyl-1,2-propane, 3-phenyl-1,2-epoxypropane and the like can be mentioned.

Examples of the monovalent epoxy compound represented by the above formula (V) include various alkyl glycidyl ethers.

Examples of the monovalent epoxy compound represented by the above formula (VI) include various alkylene glycol monoglycidyl ethers.

Examples of the monovalent epoxy compound represented by the above formula (VII) include various alkenyl glycidyl ethers.

Examples of the monovalent epoxy compound represented by the above formula (VIII) include various epoxy alkanols such as glycidol.

Examples of the monovalent epoxy compound represented by the above formula (IX) include various epoxy cycloalkanes.

Examples of the monovalent epoxy compound represented by the above formula (X) include various epoxy cycloalkenes.

Among the monovalent epoxy compounds, an epoxy compound having 2 to 8 carbon atoms is preferable. In particular, from the viewpoint of ease of handling of the compound and reactivity, the monovalent epoxy compound has more preferably 2 to 6 carbon atoms and further preferably 2 to 4 carbon atoms. Further, the monovalent epoxy compound is particularly preferably a compound represented by the formula (IV) and a compound represented by the formula (V) among the above formulas. Specifically, 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, epoxyethane and glycidol are preferable from the viewpoint of reactivity with EVOH and gas barrier property of the obtained laminate. Epoxypropane and glycidol are particularly preferred.

In the structural unit (III), R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are preferably hydrogen atoms and aliphatic hydrocarbon groups having 1 to 5 carbon atoms. In particular, as the aliphatic hydrocarbon group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group and a pentyl group are preferable.

The method for incorporating the structural unit (III) in EVOH is not particularly limited, and for example, it can be produced by the method described in JP-A-2014-304647.

When the above-mentioned laminated film is adopted as the structure of the film according to the present embodiment, the polymer (material for forming the A layer) forming the A layer may be one or more of a phosphoric acid compound, a carboxylic acid, a boron compound, a metal salt and the like. Seed additives can be added. By adding these additives to the polymer of the A layer, various performances of the laminated film can be improved.

The polymer forming the A layer may be composed of only the gas barrier resin, or may contain a resin other than the gas barrier resin. Further, the layer A (material for forming the layer A) may contain various components such as a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, and a filler in addition to the above polymer.

[Elastomer]
The elastomer is a polymer that is the main component of the B layer. The lower limit of the content of the elastomer in the B layer (material for forming the B layer) is, for example, 60% by mass, preferably 90% by mass, more preferably 95% by mass, further preferably 97% by mass, and further preferably 99% by mass. It may be preferable, and 99.9% by mass may be more preferable. The above-mentioned elastomer is a resin having elasticity near room temperature, and is a component that imparts stretchability. Specifically, a resin having a property of being stretched twice at 20 ° C., held in that state for 1 minute, then released from tension and contracted to less than 1.5 times the original length within 1 minute. Say. Elastomers are structurally usually polymers having hard and soft segments in the polymer chain. Also, elastomers are usually thermoplastic.

Examples of the elastomer include hydrocarbon-based elastomers (styrene-based elastomers, olefin-based elastomers, diene-based elastomers, etc.), vinyl chloride-based elastomers, chlorinated polyethylene-based elastomers, polyurethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, and fluororesin-based elastomers. Elastomers and the like can be mentioned.

When the laminated film is adopted as the structure of the film according to the present embodiment, the laminated film is formed of one or a plurality of elastomer layers (B1) formed of a polymer containing a hydrocarbon-based elastomer as the B layer (hereinafter, "B1"). It is preferable that at least one of the B1 layers is laminated as the outermost layer (outer elastomer layer). With this configuration, the adhesion between the elastomer layer (B1), which is the outermost layer, and the transport roll can be suppressed during molding of the laminated film, so that excessive stretching of the laminated film during molding can be suppressed. As a result, the length ratio L ₂ / L ₁ in the MD direction before and after the tension is applied can be controlled within a more appropriate range.

The above-mentioned hydrocarbon-based elastomer refers to an elastomer containing hydrocarbon as a main monomer unit, and examples thereof include styrene-based elastomers, olefin-based elastomers, and diene-based elastomers. Among these, styrene-based elastomers and olefin-based elastomers can be mentioned. Elastomers are preferred, and styrene-based elastomers are more preferred. Since such a hydrocarbon-based elastomer can suppress the adhesion to the transport roll because of its low polarity and the like, it is possible to suppress excessive stretching of the laminated film during molding.

(Styrene-based elastomer)
The styrene-based elastomer usually has an aromatic vinyl-based polymer block (hard segment) and a rubber block (soft segment), and the aromatic vinyl-based polymer portion forms a physical crosslink to serve as a cross-linking point. On the other hand, the rubber block imparts rubber elasticity.

Examples of the styrene-based elastomer include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-isobutylene-styrene block copolymer (SIBS), and styrene-ethylene. / Butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), and polymers obtained by modifying these copolymers can be mentioned. Of these, styrene-based elastomers having a double bond are preferable, SBS, SIS, SEBS and combinations thereof are more preferable, and SBS, SIS and combinations thereof are further preferable. For example, when a laminated film and a film-like rubber material are bonded together and applied to an inner liner of a pneumatic tire, an inner bag of an accumulator, etc., the above-mentioned specific as a styrene-based elastomer of a polymer of the B1 layer laminated on the outermost layer. By using the elastomer, the B1 layer and the rubber material can be crosslinked by vulcanization or the like, so that the adhesiveness between the elastomer layer (B1) and the rubber material can be improved.

Further, the styrene-based elastomer preferably has a functional group (hereinafter, also referred to as "functional group I") that reacts with a group contained in another layer (A layer or B2 layer described later). Thereby, the interlayer adhesiveness between the B1 layer and the other layer can be improved. Examples of the group contained in the other layer include a hydroxyl group possessed by EVOH, a group possessed by another elastomer such as a polyurethane-based elastomer (for example, a carbamate group or an isocyanate group). Examples of the functional group I include a carboxy group, an epoxy group, an amino group and the like, and a carboxy group and an epoxy group are preferable, and an epoxy group is more preferable. Furthermore, it is preferable that the styrene-based elastomer has an epoxy group in the main chain. Having an epoxy group in the main chain means having a cyclic ether structure in the main chain, and it is preferable to have a three-membered ring cyclic ether structure in the main chain.

Styrene-based elastomers having a carboxy group (carboxylic acid-modified styrene-based elastomers) include (1) a method of chemically bonding an unsaturated carboxylic acid or an anhydride thereof to a styrene-based elastomer by an addition reaction or a graft reaction, (2). It can be obtained by a method of copolymerizing a vinyl aromatic compound, a conjugated diene compound or a hydrogenated product thereof, and an unsaturated carboxylic acid or an anhydride thereof. Examples of the unsaturated carboxylic acid and its anhydride include maleic acid and maleic anhydride.

A styrene-based elastomer having an epoxy group in the main chain (epoxide-modified styrene-based elastomer) can be obtained by reacting a styrene-based elastomer or a partially hydrogenated styrene-based elastomer with an epoxidizing agent in an inert solvent or the like. .. The carbon-carbon double bond of the rubber block (soft segment) is epoxidized by the reaction with the epoxidizing agent.

Examples of the epoxidizing agent include peracids and hydroperoxides. Examples of peracids include peracetic acid, peracetic acid, perbenzoic acid, trifluoroperacetic acid and the like. Examples of the hydroperoxides include hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide and the like.

(Olefin-based elastomer)
Examples of the olefin-based elastomer include a thermoplastic elastomer having a polyolefin portion such as polypropylene or polyethylene as a hard segment and an ethylene-propylene-diene copolymer rubber portion as a soft segment. Further, maleic anhydride-modified ethylene-butene-1 copolymer, maleic anhydride-modified ethylene-propylene copolymer, butyl halide rubber, modified polypropylene, modified polyethylene and the like can also be mentioned.

(Diene elastomer)
Examples of the diene-based elastomer include 1,2-polybutadiene-based elastomers, trans-1,4-polyisoprene-based elastomers, hydrogenated conjugated diene-based elastomers, epoxidized natural rubbers, and modified maleic anhydrides thereof. ..

When the laminated film has a plurality of B layers, even if the B layer is composed of only the B1 layer or only the elastomer layer different from the B1 layer, the elastomer different from the B1 layer and the B1 layer. It may be composed of layers. Examples of the elastomer layer different from the B1 layer include an elastomer layer (B2) (hereinafter, also referred to as “B2 layer”) formed from a polymer other than the polymer containing the hydrocarbon-based elastomer. It may have one or more B2 layers. In particular, when the laminated film has one or a plurality of B2 layers as an elastomer layer (inner elastomer layer) other than the outermost layer, the stretchability can be further enhanced.

Examples of the elastomer used for the B2 layer polymer include vinyl chloride-based elastomers, chlorinated polyethylene-based elastomers, polyester-based elastomers, polyamide-based elastomers, fluororesin-based elastomers, and polyurethane-based elastomers. Among these, polyurethane-based elastomers are preferable. Stretchability can be further enhanced by using a polyurethane-based elastomer. These elastomers can be used alone or in admixture of two or more.

(Vinyl chloride elastomer)
As the vinyl chloride-based elastomer, the following three types are generally mentioned. As the vinyl chloride-based elastomer, a modified product such as a maleic anhydride-modified elastomer can also be used.
(1) High molecular weight polyvinyl (PVC) / plasticized PVC blend type (2) Partially cross-linked PVC / plasticized PVC blend type (3) PVC / elastomer alloy type

(Chlorinated polyethylene elastomer)
The chlorinated polyethylene-based elastomer is a soft resin obtained by reacting polyethylene with chlorine gas as an aqueous suspension or in a solvent such as carbon tetrachloride. The chlorinated polyethylene-based elastomer has a crystalline polyethylene portion as a hard segment and a chlorinated polyethylene portion as a soft segment.

(Polyester elastomer)
A polyester-based elastomer is a multi-block copolymer having a polyester portion as a hard segment in a molecule and a polyether portion or a polyester portion having a low glass transition temperature (Tg) as a soft segment.

(Polyamide-based elastomer)
The polyamide-based elastomer is a multi-block copolymer having a polyamide portion as a hard segment and a polyether portion or a polyester portion having a low Tg as a soft segment. The polyamide component is selected from nylon 6, 66, 610, 11, 12, and the like, and nylon 6 or nylon 12 is generally used. A long-chain polyol of a polyether diol or a polyester diol is used as a component of the soft segment. Examples of the polyether include poly (oxytetramethylene) glycol (PTMG) and poly (oxypropylene) glycol. Examples of the polyester diol include poly (ethylene adipate) glycol and poly (butylene-1,4-adipate) glycol.

(Fluororesin-based elastomer)
The fluororesin-based elastomer is an ABA-type block copolymer composed of a fluororesin portion as a hard segment and a fluororubber portion as a soft segment. As the hard segment fluororesin, tetrafluoroethylene-ethylene copolymer polymer, polyvinylidene fluoride (PVDF) and the like are used. As the fluororubber of the soft segment, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene ternary copolymer or the like is used.

(Polyurethane elastomer)
The polyurethane-based elastomer (thermoplastic polyurethane-based elastomer: TPU) has (1) a polyurethane portion obtained by the reaction of short-chain glycol (low molecular weight polyol) and isocyanate as a hard segment, and (2) long-chain glycol (high) as a soft segment. It is a linear multi-block copolymer or the like in which a polyurethane portion obtained by a reaction of (molecular polyol) and isocyanate is used. Here, polyurethane is a general term for compounds having a urethane bond (-NHCOO-), which is obtained by a urethanization reaction of isocyanate (-NCO) and alcohol (-OH).

It is preferable to use a polyurethane-based elastomer as the polymer forming the B2 layer because the stretchability, thermoformability and the like can be improved. Further, in the laminated body, good bending resistance and the like can be exhibited due to the high interlayer adhesiveness between the B2 layer and the A layer.

TPU is composed of high molecular weight polyol, organic polyisocyanate, chain extender and the like. This polymer polyol is a substance having a plurality of hydroxyl groups, and is obtained by polycondensation, addition polymerization (for example, ring-opening polymerization), polyaddition and the like. Examples of the polymer polyol include polyester polyols, polyether polyols, polycarbonate polyols, and cocondensates thereof (for example, polyester-ether-polyester). One type of these polymer polyols may be used alone, or two or more types may be mixed and used. Of these, polyester polyols and polycarbonate polyols are preferable, and polyester polyols are particularly preferable.

For the polyester polyol, for example, an ester-forming derivative such as dicarboxylic acid, an ester thereof, or an anhydride thereof is condensed with a low molecular weight polyol by a direct esterification reaction or a transesterification reaction, or the lactone is ring-opened according to a conventional method. It can be produced by polymerization.

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene) glycol and the like. One of these polyether polyols may be used alone, or two or more thereof may be mixed and used. Of these, polytetramethylene glycol is preferable.

Examples of the polycarbonate polyol include fats having 2 to 12 carbon atoms such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and 1,10-decanediol. A group diol or a mixture thereof obtained by polycondensation by allowing diphenyl carbonate or phosgen to act is preferably used.

As the lower limit of the number average molecular weight of the polymer polyol, 500 is preferable, 600 is more preferable, and 700 is further preferable. On the other hand, the upper limit of the number average molecular weight of the polymer polyol is preferably 8,000, more preferably 5,000, and even more preferably 3,000. If the number average molecular weight of the polymer polyol is smaller than the above lower limit, the compatibility with the organic polyisocyanate is too good and the elasticity of the obtained TPU becomes poor, so that the obtained laminate has mechanical properties such as stretchability and thermoforming. There is a risk of reduced sex. On the contrary, when the number average molecular weight of the polymer polyol exceeds the above upper limit, the compatibility with the organic polyisocyanate is lowered, and it becomes difficult to mix in the polymerization process. As a result, a lump of gel-like substance is generated, etc. Therefore, a stable TPU may not be obtained. The number average molecular weight of the polymer polyol is a number average molecular weight calculated based on the hydroxyl value measured in accordance with JIS K 1577.

The organic polyisocyanate is not particularly limited, and a known organic diisocyanate generally used for producing TPU is used. Examples of this organic diisocyanate include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, phenylenediisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3'-dichloro-4,4'-diphenylmethane diisocyanate, and tolui. Aromatic diisocyanates such as range isocyanate; aliphatic diisocyanates (including alicyclic diisocyanates) such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and hydride xylylene diisocyanate can be mentioned. Among these, 4,4'-diphenylmethane diisocyanate is preferable because the strength and bending resistance of the obtained laminate can be improved. One of these organic diisocyanates may be used alone, or two or more thereof may be used in combination.

As the chain extender, a chain extender generally used in the production of TPU is used, and a low molecular weight compound having two or more active hydrogen atoms capable of reacting with an isocyanate group and having a molecular weight of 300 or less is preferable. used. Examples of the chain extender include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol and the like. .. Among these, an aliphatic diol having 2 to 10 carbon atoms is preferable, and 1,4-butanediol is particularly preferable, in that the stretchability and thermoformability of the obtained laminate are further improved. One of these chain extenders may be used alone, or two or more thereof may be mixed and used.

As a method for producing TPU, the above-mentioned polymer polyol, organic polyisocyanate and chain extender are used, and the TPU is produced by using a known urethanization reaction technique, and is produced by using either the prepolymer method or the one-shot method. can do. Among them, it is preferable to carry out melt polymerization in the absence of a solvent, and it is particularly preferable to carry out continuous melt polymerization using a multi-screw screw type extruder.

The polymer forming the B layer may be composed of only an elastomer, or may contain a polymer other than the elastomer. Further, the B layer (B layer forming material) may further contain other components such as a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, and a filler in addition to the above polymer.

[Layered film layer structure]
When the laminated film is adopted as the structure of the film according to the present embodiment, the layer structure of the laminated film is not particularly limited as long as it has one or a plurality of A layers and one or a plurality of B layers, and the A layer is not particularly limited. And may have a resin layer or the like other than the B layer.

As the lower limit of the total number of layers A and B, 3 layers are preferable, 5 layers are more preferable, 7 layers are more preferable, 9 layers are particularly preferable, and 15 layers are even more preferable. On the other hand, the upper limit of the total number of layers A and B is preferably 300 layers, more preferably 200 layers, further preferably 100 layers, and particularly preferably 50 layers. The total number of layers of the laminated film is also preferably in the above range. By setting the number of layers in the above range, it is possible to prevent the continuous occurrence of defects such as pinholes and cracks when bent, and thus the durability can be improved. In this case, it is preferable that the layer A and the layer B have a laminated structure (alternate laminated structure) in which the layers A and the B layer are alternately laminated, and the number of laminated layers of the alternate laminated structure is 7 or more. With this configuration, it is possible to further suppress the continuous occurrence of defects such as pinholes and cracks, so that the durability can be further improved. The number of layers A is preferably two or more, more preferably five or more, and even more preferably ten or more. The number of layers of the B layer is preferably 3 or more, more preferably 6 or more, and more preferably 10 or more.

The lower limit of the total thickness of all the layers A and B is preferably 10 μm, more preferably 15 μm, and even more preferably 30 μm. On the other hand, the upper limit is preferably 500 μm, more preferably 300 μm, and even more preferably 100 μm. If the total thickness of all the layers A and B is less than the above lower limit, the strength, bending resistance, durability, gas barrier property, etc. may decrease. On the contrary, when the total thickness exceeds the above upper limit, the flexibility, moldability, etc. are lowered, which may lead to a decrease in bending resistance and an increase in manufacturing cost. Here, the total thickness of all layers means the total average thickness of each layer. The average thickness of each layer is the average value of the cross-sectional thickness at 10 arbitrarily selected points.

The lower limit of the average thickness of one layer of the A layer is preferably 0.1 μm, more preferably 0.2 μm, and even more preferably 0.3 μm. On the other hand, as the upper limit, 15 μm is preferable, 5 μm is more preferable, 3 μm is further preferable, 2 μm is further preferable, 1 μm is further preferable, and 0.5 μm is particularly preferable. If the average thickness of one layer A is smaller than the above lower limit, it becomes difficult to mold with a uniform thickness, and the gas barrier property, durability, and the like may deteriorate. On the contrary, if the average thickness of one layer A exceeds the above upper limit, the flexibility and the like may decrease, and as a result, the durability and the like may also decrease.

The lower limit of the average thickness of one layer of the B layer (B1 layer and / or B2 layer) is preferably 0.1 μm, more preferably 0.5 μm, further preferably 1 μm, and particularly preferably 2.5 μm. On the other hand, as the upper limit, 30 μm is preferable, 15 μm is more preferable, 10 μm is further preferable, 8 μm is further preferable, and 6 μm is particularly preferable. If the average thickness of one layer B is smaller than the above lower limit, it becomes difficult to mold with a uniform thickness, and the durability may decrease. In addition, sufficient flexibility may not be exhibited. On the contrary, if the average thickness of one B layer exceeds the above upper limit, the interlayer adhesiveness and gas barrier property may be deteriorated.

In particular, the lower limit of the average thickness of the B1 layer laminated as the outermost layer is preferably 0.1 μm, more preferably 0.5 μm, further preferably 1 μm, and particularly preferably 3 μm. On the other hand, as the upper limit, 20 μm is preferable, 8 μm is more preferable, and 6 μm is further preferable. By setting the average thickness of the B1 layer laminated as the outermost layer in the above range in this way, the adhesiveness to the rubber material is enhanced, for example, when the B1 layer is formed of a polymer containing a styrene-based elastomer. be able to.

Examples of the laminated film having a preferable layer structure in the present embodiment include the laminated film 10 shown in FIG. 1 (a) and the laminated film 20 shown in FIG. 1 (b). The laminated film 10 shown in FIG. 1A is composed of a plurality of A layers 1, a pair of B1 layers 2, and a plurality of B2 layers 3. In the laminated film 10, the B1 layer 2 is laminated on both outer surfaces (the surface of the B2 layer 3) of the alternating laminated structure of the A layer 1 and the B2 layer 3. The laminated film 20 shown in FIG. 1B is composed of a plurality of A layers 1 and a plurality of B1 layers 2. The laminated film 20 has an alternating laminated structure of A layer 1 and B1 layer 2 having B1 layer 2 as both outermost layers.

In both the laminated film 10 and the laminated film 20, the B1 layer 2 is arranged on both outermost layers. By arranging the B1 layer 2 in both outermost layers, it is possible to suppress the adhesion between both outermost layers and the transport roll during molding of the laminated film, so that excessive stretching of the laminated film during molding can be suppressed. Further, the laminated film 10 and the laminated film 20 have a symmetrical layer structure. By adopting a symmetrical structure, each layer can be efficiently formed by coextrusion. The B1 layer 2 may not be laminated as the outermost layers on both sides, or may be laminated only as the outermost layer on one side.

[Oxygen permeability coefficient of film]
The upper limit of the oxygen permeability coefficient of the film according to the present embodiment is 200 mL / (m ² · day · atm), preferably 170 mL / (m ² · day · atm), and 150 mL / (m ² · day · atm). ) Is more preferable, 100 mL / (m ² · day · atm) is even more preferable, and 50 mL / (m ² · day · atm) is particularly preferable. By setting the oxygen permeability coefficient to be equal to or lower than the preferable upper limit, the gas barrier property can be further improved. On the other hand, the lower limit of the oxygen permeability coefficient is not particularly ^{limited, 0.1mL / (m 2 · day} · atm) in terms of reduction in manufacturing cost are preferred. The oxygen permeability coefficient of the film can be controlled by adjusting the type of gas barrier resin used, the thickness of the A layer in the case of a laminated film, the number of laminated films, and the like.

[Length ratio in the MD direction before and after applying tension to the film]
The upper limit of the length ratio L ₂ / L ₁ in the MD direction of the film according to the present embodiment before and after applying the tension is 1.5, preferably 1.4, more preferably 1.3, and 1.28. Is more preferable, and 1.25 is particularly preferable. By setting the length ratio L ₂ / L ₁ to be equal to or less than the above preferable upper limit, it is possible to further suppress a decrease in gas barrier property due to use. On the other hand, the lower limit of the length ratio L ₂ / L ₁ is not particularly limited, but is preferably 0.7, more preferably 0.8, and particularly 1.0 from the viewpoint of dimensional stability during repeated use. preferable. The length ratio L ₂ / L ₁ of the film is the type of gas barrier resin and elastomer used, the thickness and number of layers of each layer in the case of a laminated film, the pressure of the air slit during film molding described later, the draw ratio, and the like. It can be controlled by adjusting.

[Film breaking elongation ratio]
When the elongation at break in the MD direction and the TD direction of the film according to the present embodiment was _{E MD} and _{E TD,} respectively, the lower limit of the ratio _E TD _{/ E MD} elongation at break, preferably 0.9, 1. 0 is more preferred, 1.1 is even more preferred, 1.2 is particularly preferred, and 1.3 is most preferred. The upper limit of the breaking elongation ratio _E TD _{/ E MD,} preferably 1.7, 1.6 is more preferable. While improving the impact resistance by the breaking elongation ratio E _{TD /} E _MD in the above range can further suppress the decrease in the gas barrier property due to the use. The breaking elongation ratio E _{TD /} E _MD of the film, the kind of the gas barrier resin and elastomer used, the thickness of each layer and number of layers in the case of a laminated film, the pressure of the air slit during later-described film molding and draw ratio, etc. Can be controlled by adjusting. Incidentally, _{E MD} of the film according to the present embodiment is 800% or less, for example, 200% or more. Also, _{E TD} of the film according to the present embodiment is 800% or less, for example, 200% or more.

[Use, etc.]
Since the film of the present embodiment has a gas barrier resin and an elastomer, it is excellent in gas barrier property, stretchability, and the like. Therefore, the film of this embodiment is suitable for a stretch film. In particular, the film of the present embodiment is suitable as a stretch film that is repeatedly used because it can suppress a decrease in gas barrier property due to use. Further, the film of the present embodiment is a molded body provided with a protective layer, an embossed layer, a rubber layer, etc. on the outer surface, and includes various sheet materials such as a curing sheet, an inner liner for pneumatic tires, a silage film, a gasket, and an accumulator. Suitable for inner bags, pneumatic balls, air springs, etc.

<Film manufacturing method>
As a method for producing a film according to an embodiment of the present invention, the above-mentioned method for producing a laminated film having an A layer and a B layer will be described.

The method for producing the laminated film is not particularly limited as long as the A layer and the B layer are satisfactorily laminated and bonded, and for example, known coextrusion, bonding, coating, bonding, adhesion and the like are known. The method can be adopted.

As a method for producing the laminated film, a production method including a step of co-extruding a polymer forming the A layer (A layer forming material) and a polymer forming the B layer (B layer forming material) is preferable. According to this manufacturing method, since the A layer and the B layer can be molded at the same time, a laminated film having the above characteristics can be easily and surely manufactured.

In the multi-layer coextrusion method, the polymer forming the A layer and the polymer forming the B layer are heated and melted and supplied to the extrusion die from different extruders and pumps through their respective flow paths, and the extrusion die is multi-layered. It is extruded in a state to form the laminated film. As the extrusion die, for example, a multi-manifold die, a field block, a static mixer or the like can be used.

Regarding the relationship between the viscosities of the polymers forming the A layer and the B layer, the following melt viscosity ratio is preferable. That is, the lower limit of the ratio (η _B / η _A ) of the melt viscosity (η _A ) of the polymer of the A layer to the melt viscosity (η _B ) of the polymer of the B layer at a temperature of 210 ° C. and a shear rate of 1,000 / sec. Of the above, 0.3 is preferable, and 0.5 is more preferable. On the other hand, as the upper limit of this melt viscosity ratio (η _B / η _A ), 2 is preferable, and 1.5 is more preferable. By setting the melt viscosity ratio (η _B / η _A ) in the above range, the appearance of the laminated film is improved, and the adhesion between the A layer and the B layer is improved, so that the durability of the laminated film is improved. Etc. can be improved.

The method for producing a laminated film preferably includes a step of irradiating a structure (laminated body) obtained by coextrusion with an electron beam. By the electron beam irradiation, a cross-linking reaction occurs between the layers, and the interlayer adhesive force of the obtained laminated film can be enhanced. As the electron beam source, various electron beam accelerators such as a cockloft Walton type, a bandegraft type, a resonance transformer type, an insulated core transformer type, a dynamitron type, and a high frequency type can be used.

As a specific example of a preferable manufacturing method in the present embodiment, an example of manufacturing a laminated film having a three-layer structure in which a B layer is laminated on both sides of the A layer will be described with reference to FIG. The film forming apparatus shown in FIG. 2 includes an extrusion die 70 for extruding a polymer (polymer 60 / polymer 50 / polymer 60), a first transfer roll 80 for conveying a laminate 100 made of the polymer extruded from the extrusion die 70, and a first transfer roll 80. A second transport roll 90 and an air slit 110 arranged on the opposite side of the laminated body 100 from the first transport roll 80 are provided. With this film forming apparatus, the polymer 50 forming the A layer and the polymer 60 forming the B layer are co-extruded from the extrusion die 70, and the laminate 100 made of the polymer extruded from the extrusion die 70 is first conveyed to the roll. A laminated film can be obtained by stretching while being conveyed by the 80 and the second conveying roll 90 or the like. In FIG. 2, hatching indicating a cross-sectional structure is omitted for the extrusion die 70, the first transfer roll 80, the second transfer roll 90, and the air slit 110.

When the laminated body 100 is conveyed, when the rotation speed of the first transfer roll 80 is R ₁ and the rotation speed of the second transfer roll 90 is R ₂ , the rotation speed ratio (R ₂ / R ₁ ) (hereinafter, “ The larger the draw ratio), the more the orientation of the polymer crystals of the gas barrier resin contained in the polymer 50 in the MD direction can be promoted. The lower limit of the draw ratio is preferably 1.0, more preferably 1.05. The upper limit of the draw ratio is preferably 1.5, more preferably 1.4. By setting the draw ratio within the above range, the orientation of the laminated film in the MD direction can be appropriately adjusted. Further, if air A is blown from the air slit 110 to the laminated body 100 to accelerate the contact between the laminated body 100 and the first transport roll 80, the stretching process time becomes long. Therefore, this method also allows the laminated film to move in the MD direction. Orientation can be promoted. At this time, the stretching process time can be controlled by adjusting the pressure of the air introduced into the air slit 110. The lower limit of the pressure of the air introduced into the air slit 110 is preferably 0.01 MPa, more preferably 0.05 MPa. The upper limit of the pressure of the air A is preferably 0.5 MPa, more preferably 0.4 MPa. By setting the pressure at the time of introduction into the air slit 110 within the above range, the orientation of the laminated film in the MD direction can be appropriately adjusted. As the orientation of the laminated film in the MD direction is promoted, the length ratio L ₂ / L ₁ and the breaking elongation ratio _ETD / E _MD of the laminated film in the MD direction tend to increase.

<Molded body>
The molded product according to the embodiment of the present invention includes the film according to the embodiment of the present invention described above. The molded product of the present embodiment can be obtained, for example, by providing a protective layer, an embossed layer, a rubber layer, or the like on the outer surface of the film. As described above, this molded product is suitably used for various sheet materials such as curing sheets. According to the molded product of the present embodiment, since the film is provided, for example, the gas barrier of the film even if the film is stretched by applying tension when molding the molded product or repeatedly tensioned during use. Can maintain sex.

It is preferable that the molded product of the present embodiment further includes a diene rubber layer (C) (hereinafter, also referred to as “C layer”) laminated on the outer surface of the film. With this configuration, it can be applied to, for example, an inner liner of a pneumatic tire, an inner bag of an accumulator, a pneumatic ball, an air spring, and the like.

Examples of the molded product having a preferable structure include the molded product 30 shown in FIG. 3 (a) and the molded product 40 shown in FIG. 3 (b). The molded body 30 shown in FIG. 3A is formed by laminating the C layer 4 on one outer surface of the laminated film 10 of FIG. 1A. The molded body 40 shown in FIG. 3B is obtained by laminating the C layer 4 on one outer surface of the laminated film 20 of FIG. 1B.

In the molded product of the present embodiment, the C layer may be laminated on both outer surfaces of the film. Further, the molded product of the present embodiment may have a resin layer or the like other than the A layer, the B layer and the C layer.

In the molded product of the present embodiment, the A layer and the B layer (B1 layer and B2 layer) are the same as those of the above-mentioned laminated film.

The C layer is formed of a rubber material containing a diene rubber. The diene-based rubber refers to a rubber having a carbon-carbon double bond in the main chain. Examples of the diene rubber include natural rubber (NR), isoprene rubber (IR), cis-1,4-polybutadiene (BR), syndiotactic-1,2-polybutadiene (1,2BR), and styrene-butadiene co-weight. Examples thereof include coalesced rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR). One of these diene rubbers may be used alone, or two or more of them may be mixed and used.

The C layer may be formed only of the diene rubber, but may contain a component other than the diene rubber as long as the effect of the present invention is not impaired. Examples of other components include softeners, antiaging agents, vulcanizing agents, vulcanization accelerators, vulcanization accelerator aids, scorch inhibitors, zinc oxide, stearic acid, fillers and the like.

The average thickness of one layer of the C layer is not particularly limited, but the lower limit is preferably 10 μm, more preferably 100 μm. On the other hand, as the upper limit, 5 mm is preferable, and 1 mm is more preferable.

In FIGS. 3A and 3B, the C layer 4 and the B1 layer 2 adjacent to the C layer 4 are bonded at an interface by, for example, a cross-linking reaction (vulcanization reaction). In particular, when the B1 layer 2 is formed of a polymer containing a styrene-based elastomer containing a double bond, the above-mentioned cross-linking reaction can be easily carried out.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[Manufacturing of pellets]
85.1 parts by mass of vinyl acetate, 26.4 parts by mass of methanol, and 2,2'-azobis- (4-methoxy-2,4-dimethylvaleronitrile) as a polymerization initiator in a polymerization tank having a cooling device and a stirrer. 0.56 parts by mass of a methanol solution dissolved at 2.0 g / L was charged therein, and after nitrogen substitution with stirring, ethylene was introduced at a temperature of 60 ° C. and a pressure of 3.7 MPa, which was the same as the methanol solution of the above-mentioned polymerization initiator. The solution of the composition was added at a rate of 1.7 parts by mass / hr, and the temperature and pressure were maintained and the mixture was stirred for 4 hours for polymerization. Then, 0.0426 parts by mass of sorbic acid (0.05% by mass with respect to the charged vinyl acetate) was dissolved in methanol to prepare a 1.5% by mass solution and added. The polymerization rate was 40% with respect to the charged vinyl acetate. This copolymerization reaction solution was supplied to a separation column, and unreacted vinyl acetate was removed from the column top by introducing methanol vapor from the lower part of the column, and then a 40% by mass methanol solution of this copolymer was obtained.

A methanol solution of the obtained copolymer was introduced into a saponification reactor, and a methanol solution of sodium hydroxide (85 g / L) was added so as to have an amount of 0.5 equivalent with respect to the vinyl acetate component in the copolymer. Then, methanol was further added to adjust the copolymer concentration to 15% by mass. The temperature inside the reactor was raised to 60 ° C., and the reaction was carried out for 5 hours while blowing nitrogen gas into the reactor. Then, it was neutralized with acetic acid to stop the reaction, the contents were taken out from the reactor, and left at room temperature to precipitate in the form of particles. The precipitated particles were deflated with a centrifuge, and the operation of adding a large amount of water to deflate was repeated to obtain EVOH having an ethylene unit content of 32.0 mol% and a saponification degree of 99.5%.

The obtained EVOH is treated with an acetic acid aqueous solution (acetic acid concentration 0.5 g / L) at a bath ratio of 20 (mass ratio of acetic acid aqueous solution / EVOH is 20), dried, pelletized by an extruder, and EVOH. Pellets (A-1) were obtained. The melt flow rate (MFR) of the pellet (A-1) was 5.8 g / 10 minutes (temperature 190 ° C., load 2160 g), and the acetic acid content was 400 mass ppm. Further, the Tg of the pellet (A-1) was measured by the DSC device "Q2000" of TA Instrument Co., Ltd. according to JIS K 7121 (2012) and found to be 57 ° C. The Tg of the resin used for the gas barrier layer described below was also measured in the same manner as described above.

Using the pellet (A-1) obtained above, Toshiba Machine Co., Ltd.'s twin-screw extruder "TEM-35BS" (screw diameter (D) 37 mm, screw length (L) / screw diameter (D) = 52. Using 5), 1,2-epoxybutane was reacted with EVOH under the following extrusion conditions under the addition of a catalyst, unreacted 1,2-epoxybutane was removed from the vent, and then ethylenediamine-4 was used as a catalyst deactivator. An 8.0% by mass aqueous solution of trisodium acetate hydrate is added, pelletized, and then dried to have the following structure as a structural unit (II) other than ethylene unit and vinyl alcohol unit 1,2-. Pellets (A-2) containing epoxybutane-modified EVOH were obtained.

(Extrusion conditions)
Cylinder and die temperature settings: Resin feed port / Cylinder inlet / Adapter / Die = 160 ° C / 200 ° C / 240 ° C / 240 ° C
Screw rotation speed: 400 rpm
Ethylene-vinyl alcohol copolymer feed amount: 15 kg / hr
1,2-Epoxybutane feed amount: 2.8 kg / hr (pressure at the time of feed 6 MPa)
Catalyst solution feed amount: 0.32 kg / hr
Catalyst preparation method: 28 parts by mass of zinc acetylacetonate monohydrate was mixed with 957 parts by mass of 1,2-dimethoxyethane to obtain a mixed solution. To the obtained mixed solution, 15 parts by mass of trifluoromethanesulfonic acid was added with stirring to obtain a catalytic solution. That is, a solution was prepared by mixing 1 mol of trifluoromethanesulfonic acid with 1 mol of zinc acetylacetonate monohydrate.
Aqueous catalyst deactivator feed amount: 0.15 kg / hr

The MFR of the obtained pellet (A-2) was 3.5 g / 10 minutes (temperature 190 ° C., load 2160 g). The pellet (A-2) has an acetic acid content of 420 mass ppm, a zinc ion content of 140 mass ppm, a sodium content of 140 mass ppm, a phosphoric acid compound content of 20 mass ppm in terms of phosphoric acid root, and trifluoromethane. The sulfonate ion content was 290 mass ppm. The amount of EVOH structural unit (II) introduced (1,2-epoxybutane modification amount) constituting the pellet (A-2) is ^{1 1} H-NMR (internal standard substance: tetramethylsilane, solvent: d _6-). The value obtained by DMSO) was 6.7 mol%.

Further, in the process of obtaining pellets (A-2) using pellets (A-1), pellets were produced under the same conditions except that epoxy propane was used instead of epoxy butane, and the ethylene unit content was 32. Pellets (A-3) containing EVOH of 0 mol% and an epoxy propane modification amount of 6.7 mol% were obtained.

Hereinafter, details of the resin used for the gas barrier layer of Examples other than the above-mentioned (A-1), (A-2) and (A-3) will be shown.
(A-4) Kuraray's EVOH "EVAL L171"; ethylene unit content 27 mol%
(A-5) Kuraray's EVOH "EVAL E171"; ethylene unit content 44 mol%
(A-6) Toray Industries, Inc. Nylon 6 "Amiran CM1021FS"
(A-7) Polylactic acid (PLA) "PLA6201D" from Nature Works Japan

[Manufacturing of polymethallyl alcohol (A-8)]
After replacing the inside of the autoclave equipped with a stirrer and a sampling tube with nitrogen, 100 parts by mass of purified methyl methacrylate, 0.0052 parts by mass of 2,2'-azobis (2-methylpropionitrile), and n- 0.28 parts by mass of octyl mercaptan was added and stirred to obtain a raw material solution. Nitrogen was sent into the raw material liquid to remove dissolved oxygen in the raw material liquid. The above raw material liquid was put into a tank reactor connected to the autoclave by piping up to 2/3 of the capacity. The temperature was maintained at 140 ° C., and the polymerization reaction was first started by a batch method. When the polymerization conversion rate reaches 55%, the raw material liquid is supplied from the autoclave to the tank reactor at a flow rate having an average residence time of 150 minutes, and the reaction liquid is supplied at a flow rate corresponding to the supply flow rate of the raw material liquid. It was taken out from the tank reactor, maintained at a temperature of 140 ° C., and switched to a continuous flow type polymerization reaction. After switching, the polymerization conversion rate in the steady state was 55%.

The reaction solution extracted from the tank reactor in a steady state was supplied to a multi-tube heat exchanger having an internal temperature of 230 ° C. at a flow rate having an average residence time of 2 minutes for heating. Next, the heated reaction solution was introduced into an adiabatic flash evaporator to remove volatile components containing unreacted monomers as a main component to obtain a molten resin. The molten resin from which the volatile matter has been removed is supplied to a twin-screw extruder having an internal temperature of 260 ° C., discharged in a strand shape, cut with a pelletizer, and has a Tg of 120 ° C. and a proportion of structural units derived from methyl methacrylate. A pellet-shaped methacrylic resin having a mass content of 100% by mass was obtained.

Next, 250 parts by mass of lithium aluminum hydride was charged into a reaction vessel equipped with a cooler, substituted with nitrogen, 3,000 parts by mass of N-methylmorpholine was added, and then the mixture was heated to 130 ° C. and refluxed. A solution consisting of 600 parts by mass of the methacrylic resin synthesized above and 24 kg (6,000 parts by mass) of N-methylmorpholine was added thereto, and the mixture was refluxed for another 4 hours after the completion of the dropping. Then, 1,000 parts by mass of ethyl acetate was added dropwise to inactivate the unreacted hydride, and 5,000 parts by mass of a 50% by mass aqueous phosphoric acid solution was added dropwise. After cooling, it was separated into a supernatant and a solid content by centrifugation. The obtained supernatant was added to distilled water to precipitate the polymer 1. Further, 10,000 parts by mass of ethanol was added to the obtained solid content, dissolved by heating at 60 ° C. for 1 hour, filtered through a glass filter, the obtained filtrate was concentrated by an evaporator, and added to distilled water to form a polymer. 2 was precipitated. The polymers 1 and 2 obtained by precipitation were combined, added to distilled water at 100 ° C., and boiled for thorough washing. After washing, the mixture was filtered and dried in a hot air dryer at 80 ° C. for 3 hours and then at 120 ° C. for 24 hours to obtain polymethallyl alcohol as a resin (A-8).

[Manufacturing of TPU pellets (B2-1)]
Polytetramethylene ether glycol containing 20% by mass of dibutyltin diacetate (“PTMG2000” by Mitsubishi Chemical Corporation) 74.2% by mass, 4,4'-diphenylmethane diisocyanate 21.4% by mass, 1,4-butanediol 3. Continuously supplied to a twin-screw extruder (L / D = 30) by a metering pump in a liquid state under heating at a ratio of 9% by mass and 0.6% by mass of 3-methyl-1,5-pentanediol. Polymerization was carried out at 260 ° C. Then, it was pelletized to produce TPU pellets (B2-1).

[Manufacturing of TPU pellets (B2-2)]
The number of hydroxyl groups per molecule obtained by reacting 1,4-butanediol with adipic acid is 2.0 mol, and the number average molecular weight is 1,000. 68.8% by mass of polyester diol, 4 , 4'-Diphenylmethane diisocyanate 27.5% by mass, and 1,4-butanediol 3.7% by mass are melt-kneaded in a multi-screw screw type extruder (die temperature 260 ° C.) for 20 minutes to TPU. (Shore A hardness according to JIS B 7727 (2000): 85) was manufactured. Then, it was pelletized to obtain TPU pellets (B2-2).

In addition to (B2-1) and (B2-2) described above, details of the elastomer used for the inner elastomer layer of Examples and Comparative Examples are shown below.
(B2-3) Kuraray's ether type TPU "Chramiron 9180"
(B2-4) Polyamide-based elastomer pellet "E40-S1" from DAICEL EVONIK
(B2-5) Ube Industries, Ltd. Polyamide 12 Elastomer Pellet "UBESTA XPA"
(B2-6) Maleic anhydride-modified ethylene-butene copolymer elastomer pellet "Toughmer MH7010" from Mitsui Chemicals, Inc.
(B2-7) Mitsui Chemicals, Inc. Maleic anhydride-modified ethylene-propylene copolymer elastomer pellet "Toughmer MP0610"

The details of the elastomer used for the outer elastomer layer of Examples and Comparative Examples are shown below.
(B1-1) Daicel's epoxy-modified SBS "Epofriend AT501"
(B1-2) Daicel's epoxy-modified SBS "Epofriend CT310"
(B1-3) Maleic anhydride-modified SBS "Toughprene 912" from Asahi Kasei Chemicals Co., Ltd.
(B1-4) Asahi Kasei Chemicals' unmodified SBS (styrene / butadiene ratio 40/60) "Tough Plane A"
(B1-5) JSR's SIS (styrene / isoprene ratio 20/80) "SIS5250"
(B1-6) Zeon Corporation's SIS (styrene / isoprene ratio 48/52) "Quintac 3390"
(B1-7) Maleic anhydride-modified hydrogenated SBS "FG1901" from Kraton Polymer Japan
(B1-8) Mitsubishi Chemical Corporation's olefin-based thermoplastic elastomer "Thermoran 3755B / N"

[Example 1]
Using EVOH pellets (A-2), TPU pellets (B2-1) and SBS pellets (B1-1), 17 layers of gas barrier layers (EVOH pellets (A-2)) and inner elastomer layers (TPU pellets (TPU pellets)) were alternately used. 35 layers (gas barrier layer + inner elastomer layer) + 2 so that a laminated film in which 18 layers of B2-1)) are laminated and an outer elastomer layer (SBS pellet (B1-1)) is laminated as both outermost layers can be obtained. Each polymer was supplied to the coextruder in a molten state at 185 ° C. in a feed block for a total of 37 layers (outer elastomer layer). The polymers were then merged by coextrusion to form a multi-layered laminate. At this time, the thickness of each layer of the extruded laminate is made uniform by changing the flow path of the polymer forming each layer in the feed block so as to gradually increase the thickness from the surface layer side to the center side. I made it. The laminate consisting of a total of 37 layers thus obtained was extruded onto a casting roll (corresponding to the first transport roll 80 in FIG. 2) maintained at a surface temperature of 30 ° C. Further, an air slit having an air ejection port gap of 0.3 mm is provided at a height of 3 cm from the casting roll, and the rotation speed R ₁ of the casting roll and the cooling roll (corresponding to the second transport roll 90 in FIG. 2) are provided. ) to allow control of the speed ratio between the rotational speed _{R 2} of the was a draw ratio _{(R 2 / R 1) =} 1.0. Then, the air pressure from the air slit was controlled to 0.2 MPa, the laminated body was brought into contact with the casting roll by blowing air, and the laminated body was wound by the cooling roll to obtain the laminated film of Example 1. It takes about 4 minutes from the merging of the melts of EVOH pellets (A-2), TPU pellets (B2-1) and SBS pellets (B1-1) to quenching and solidification on the casting roll. The flow path shape and the total discharge amount were set as described above.

The laminated film obtained as described above was cross-sectionally observed with a shape measurement laser microscope "VK-X200" manufactured by KEYENCE CORPORATION, and the average thickness of one layer of each layer was measured at 10 randomly selected points. As a result, the average thickness of each one of the gas barrier layer, the inner elastomer layer and the outer elastomer layer was 0.3 μm, 2.9 μm and 5.0 μm. The total thickness of all layers was 67.3 μm.

[Examples 2-32 and Comparative Examples 1, 4, 5]
Same as Example 1 above, except that the type of polymer (resin material) of each layer, the number of layers, the average thickness of one layer, the air pressure of the air slit, and the draw ratio are changed as shown in Tables 1 and 2. The laminated films of Examples 2 to 32 and Comparative Examples 1, 4 and 5 were obtained.

[Evaluation of the physical properties]
Various physical properties of the obtained laminated film were evaluated by the methods described below. The results are shown in Tables 3 and 4.

(Oxygen permeability coefficient OTR ₁ )
Regarding the obtained laminated film, MODERN CONTROLS INC. The method described in JIS K 7126-2 (2006) (isopressure method) under the conditions of a temperature of 20 ° C. and a relative humidity of 65% using the oxygen permeability coefficient measuring device "MOCONOX-TRAN2 / 20 type" of the same company. The oxygen permeability coefficient was measured accordingly, and the oxygen permeability coefficient obtained by this measurement was defined as OTR ₁ .

(Length ratio in MD direction before and after tension application L ₂ / L ₁ )
A square of 10 cm in the MD direction x 10 cm in the TD direction is drawn in the center of the sample obtained by cutting the laminated film in the MD direction 20 cm × TD direction 20 cm, and a straight line extending in the MD direction through the center of gravity of this square is cut into the square. The length of was L ₁ . Then, in an environment of 20 ° C., both ends of this sample in the MD direction were grasped to apply tension, and the sample was stretched in the MD direction at a stretching ratio of 2 times. This stretched state was maintained for 30 seconds, after which the tension was released over 10 seconds. The length in the MD direction of the portion corresponding to the measurement location of L ₁ after the tension was released was measured, and the length was defined as L ₂ . Then, by dividing _{L 2} at _{L 1,} it was calculated MD direction length ratio _L 2 / _{L 1} before and after applying tension.

(Break elongation ratio _ETD / _EMD )
Temperature 23 ° C., under a relative humidity of 50% to measure the elongation at break elongation at break _{(E MD)} and TD direction MD direction of the laminated film _{(E TD)} in accordance with ISO 527-2, the ratio E _TD / E _MD was calculated.

(Oxygen permeability coefficient ratio before and after tension application OTR ₂ / OTR ₁ )
Regarding the laminated film after measuring the length ratio L ₂ / L ₁ in the MD direction, MODERN CONTROLS INC. The method described in JIS K 7126-2 (2006) (isopressure method) under the conditions of a temperature of 20 ° C. and a relative humidity of 65% using the oxygen permeability coefficient measuring device "MOCONOX-TRAN2 / 20 type" of the same company. The oxygen permeability coefficient was measured accordingly, and the oxygen permeability coefficient obtained by this measurement was defined as OTR ₂ . Then, this OTR ₂ was divided by the OTR ₁ measured above to calculate the oxygen permeability coefficient ratio OTR ₂ / OTR ₁ . When this value is 1.5 or less, it is judged that the decrease in gas barrier property after tension is applied with use can be suppressed.

(Impact resistance)
The impact strength was measured by a "film impact tester" manufactured by Toyo Seiki Seisakusho Co., Ltd. in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50% using a hemispherical impact head having a diameter of 1/2 inch. The measurement was performed 10 times per level, and the average value of the 10 measurements was calculated. The impact resistance of the film was evaluated based on the following evaluation criteria.
A: Impact strength 20J or more B: Impact strength 18J or more and less than 20J C: Impact strength 16J or more and less than 18J D: Impact strength 14J or more and less than 16J E: Impact strength less than 14J

As is clear from Tables 3 and 4, the oxygen permeability coefficient ratio OTR ₂ / OTR ₁ was 1.5 or less in each of the examples. On the other hand, in all the comparative examples, the oxygen permeability coefficient ratio OTR ₂ / OTR ₁ exceeded 1.5. From this result, it can be seen that according to the present invention, it is possible to suppress a decrease in gas barrier property due to use.

In comparison between the respective embodiments, breaking elongation ratio _E TD _{/ E MD} of 1.1 or more embodiments 1～5,9,11 and 16, the breaking elongation ratio _E TD _{/ E MD} 1. The impact resistance was good (A evaluation or B evaluation) as compared with other examples of less than 1. From this result, it can be seen that the impact resistance can be improved by setting the breaking elongation ratio _ETD / _EMD to 1.1 or more.

According to the present invention, it is possible to provide a film capable of suppressing a decrease in gas barrier property due to use, a molded product using the same, and a method for producing the film.

1 Layer A (Gas barrier layer (A))
2 B1 layer (elastomer layer (B1))
3 B2 layer (elastomer layer (B2))
4 C layer (diene rubber layer (C))
10, 20 Laminated film 30, 40 Molded body 50 Polymer forming layer A 60 Polymer forming layer B 70 Extruded die 80 First transport roll 90 Second transport roll 100 Laminated body 110 Air slit

Claims (11)

It contains a gas barrier resin having a glass transition temperature of 70 ° C. or less and an elastomer.
Oxygen permeability coefficient ^{200mL / (m 2 · day ·} atm) or less,
By applying tension in the MD direction at 20 ° C., the stretched state at a stretching ratio of 2 is maintained for 30 seconds, the length in the MD direction after the tension is released is L ₂ , and the MD before the tension is applied. Ri ratio _L 2 / _{L 1} is 1.5 der less when the length of the direction _{L 1,}
At least one gas barrier layer (A) formed from the polymer containing the gas barrier resin, and
With at least one elastomer layer (B) formed from the polymer containing the elastomer
Have,
The elastomer layer (B) has at least one elastomer layer (B1) formed of a polymer containing a hydrocarbon-based elastomer, and at least one layer of the elastomer layer (B1) is laminated as the outermost layer. the film. When the elongation at break in the MD and TD directions were respectively _{E MD} and _{E TD,} the film according to claim 1 ratio _E TD _{/ E MD} elongation at break is 0.9 to 1.7. The film according to claim 1 or 2, wherein the gas barrier resin is an ethylene-vinyl alcohol copolymer. The film according to any one of claims 1 to 3, wherein the total number of layers of the gas barrier layer (A) and the elastomer layer (B) is 7 or more. The film according to any one of claims 1 to 4, which has a laminated structure in which the gas barrier layer (A) and the elastomer layer (B) are alternately laminated. The film according to any one of claims 1 to 5, wherein the polymer forming the elastomer layer (B1) contains a styrene-based elastomer having a double bond. The film according to any one of claims 1 to 6, further comprising an elastomer layer (B2) formed of a polymer other than the polymer containing the hydrocarbon-based elastomer as the elastomer layer (B). The film according to claim 7 , wherein the polymer forming the elastomer layer (B2) contains a polyurethane-based elastomer. A molded product comprising the film according to any one of claims 1 to 8 . The molded product according to claim 9 , further comprising a diene-based rubber layer (C) laminated on the outer surface of the film. A polymer containing a gas barrier resin, the manufacturing method of the film according to the polymer comprising elastomeric claim 1, further comprising the step of co-extruding any one of claims 8.

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